Patent GB-907969-A (GB)
Title: Improvements in the cutting of lengths of material
IPC: B23D45/12
Filed: 1959-02-03
Abstract: 907,969. Sawing; severing by grinding. MARSHALL, W., and MARSHALL, F. Feb. 1, 1960 [Feb. 1, 1959], No. 3700/59. Classes 60 and 145. Solid or hollow material issuing from a machine, such as an extruding machine, is severed into lengths by a rotary saw 26 or abrasive disc which is advanced to make a given depth of cut into the material and is then translated round the material to complete the severing. The saw is mounted on a carriage 9 which is guided by rails 4, 5 and is moved at the same speed as the work, either by gripping it with forked clamps 11 or by providing adjustable stops against which the end of the work abuts. If the work rotates as well as having a longitudinal motion, the clamps are provided with rollers. The saw 26 is carried by a pivoted arm 24 on a ring 19 rotatable on a ring 18 fixed on the carriage 9 and the initial feed of the saw to set the depth of cut is provided either by moving the supporting structure 16 horizontally by an air cylinder or by rotating the arm 24 by an air cylinder on the ring 19. The ring 19 is rotated by a motor 23, an hydraulic variablespeed unit 22, reduction gear 21 and a chain or by spur gears, a variable speed motor or by ratchet gearing from an oscillating air cylinder. Current to the motor 23 is supplied through slip rings or an outside channel in the ring 19 may receive a cable which winds up or pays out as the ring rotates in opposite directions. The material to be cut passes through the clamps 11 and over supporting rollers 15 to one or more discharge tables comprising a V-trough formed by rollers and the cut-off lengths are discharged by tilting the whole V-trough by an air cylinder or by lowering the set of rollers on one side of the trough. In operation, the end of the material operates an adjustable flap switch on the discharge table and the clamps 11 are closed by cylinders 13. Air is also supplied to a long cylinder connected to the carriage 9 and the rate of exhaust from this cylinder is adjusted so that the material is assisted in propelling the carriage. At the same time, the motor 28 driving the saw 26 is started and an air cylinder feeds the saw into the material and, as soon as the structure 16 moves away from a pilot switch, the motor 23 is energized to rotate the ring 19. When the ring has completed one turn, a cam depresses a valve to reverse the cylinder and withdraw the structure 16 so that the pilot switch and an impulse valve are operated to stop the rotary feed, open the clamps and reverse the long cylinder for return of the carriage. The cut-off length is pushed along the discharge table until it operates a trip valve which causes air to be supplied to the cylinder for operating the V-trough to discharge the length. On completion of the stroke of this last cylinder, it operates a tappet valve to reverse the cylinder and resets a spool valve so that a new cycle can begin. A pair of handoperatedvalves duplicate the action of the trip valve and, if the carriage 9 travels too far without the clamps releasing, a projection operates a valve to shut off the main air supply and exhaust the air lines to atmosphere. For cutting non-circular sections with the version in which the saw arm 24 is rocked by an air cylinder, a sensing valve and stylus are mounted on the arm, the stylus engaging either the section itself or a cam formed by bending a strip of metal to a closed loop. Alternatively, the sensing valve and stylus may be replaced by a roller held against the cam by the air cylinder or by spring pressure.